The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
In recent years, the demand for renewable and clean sources of energy has dramatically increased. With this increase in demand, many efforts have been placed towards improving the efficiency of electricity generating wind turbines, which are powered by solar (wind) energy.
Most existing wind turbines are one of two types: (1) horizontal-axis wind turbines, or (2) vertical axis wind turbines. While horizontal-axis wind turbines are the most common throughout the world, vertical axis wind turbines are growing in popularity because they are less expensive to construct and maintain, and do not need to be positioned towards the wind, which makes them very useful in areas with varying wind directions.
In the prior art, vertical axis wind turbine foils are designed to operate in a drag configuration (Savonius design) or in a lift configuration (Darrieus design). Some examples of known vertical axis wind turbines can be found in International Patent Application Publication No. WO 2010/048,152, U.S. Patent Application Publication Nos. 2013/0115069 and 2009/0224552, and U.S. Pat. Nos. 7,303,369, 7,329,965, 7,960,852, 8,128,337, and 8,193,657.
Other examples of vertical axis wind turbines include Applicant's own wind turbines (See e.g., www.revairwind.com/gallery) and True North Bridged Composites Inc.'s wind turbines (See e.g., “Power Solution Wind Power, Everything In Our World Starts With Energy, Improving Life Through Responsible Technologies,” a power point presentation dated Mar. 30, 2012) each of which utilized lift-based foils designed to fly in a straight line and having a flat high pressure side (other than an air brake), and failed to appreciate turbine geometries to facilitate laminar flow.
Unfortunately, prior efforts apparently failed to appreciate foil designs and turbine geometries that facilitate laminar flow between foils, enhance torque, and increase efficiency.
Thus, there is still a need for improved wind power technologies.